Phylogeography of poison frog

Next Monday, Samantha will present a paper on phylogeography of poison frog in Costa Rica and Panama. In this paper, the authors try to identify the level of mitochondrial polyphyly within the species (though I don’t really understand what that means). The second aim is to identify the phylogeographic pattern of this species on its distribution range and compare it to other frogs in the same region. Find below the details of the study. Thanks Samantha.

From J. Susanne Hauswaldt, Ann-Kathrin Ludewig, Miguel Vences and Heike Prohl, Journal of Biogeography (2010) doi:10.1111/j.1365-2699.2010.02438.x

Title: Widespread co-occurrence of divergent mitochondrial haplotype lineages in a Central American species of poison frog (Oophaga pumilio)

Abstract.

Aim To analyse the phylogeographic structure of the strawberry poison frog, Oophaga pumilio (Dendrobatidae), across a large part of its range using a combination of mitochondrial and nuclear markers.

Location Costa Rica and Panama.

Methods Sequence analyses of a mitochondrial (cytochrome b) and a nuclear (RAG-1) gene fragment as well as analyses of seven microsatellite loci were carried out on 269 individuals of O. pumilio sampled from 24 localities and on two individuals of O. vicentei.

Results Two main mitochondrial haplotype lineages, corresponding to a northern (north Costa Rica) and a southern (south Costa Rica and eastern Panama) lineage, were identified. They differed by up to 7% uncorrected distance. We observed co-occurrence of both lineages in seven populations in Costa Rica and Panama, indicating a pattern of extensive admixture. The two main mitochondrial lineages of O. pumilio roughly corresponded to a previously described phylogeographic pattern. Microsatellites indicate admixture spanning over a wide geographic area, but significant variation between the northern and southern groups was also found with microsatellite data. While microsatellite data reconstructed a separation south of an assumed Caribbean valley barrier, mitochondrial haplotypes of the ‘southern lineage’ shifted this barrier towards the

north.

Main conclusions Despite admixture, all three markers showed significant variation between the northern and southern groups. Phylogeographical breaks known from other anuran species in the study region could not be verified for O. pumilio. The unexpected clustering of the population from Escudo de Veraguas and the individuals of O. vincentei with the northern O. pumilio lineage indicates the need for a fundamental and careful taxonomic revision, including an interspecific phylogeography of the entire genus.